1. Field of the Invention
The present invention relates generally to broadcast receivers. In particular, the invention concerns a receiver arranged to respond selectively to broadcast stations with a desired program content regardless of the receiver's geographic location or position.
2. Discussion of the Known Art
Contemporary broadcast stations are driven by demographic analyses, and thus focus on particular kinds of program content to capture the stations' target audiences. That is, radio listeners tend to listen for a particular kind or "type" of broadcast station that best serves their personal listening preferences. Various types of radio program content are readily identifiable upon listening to most stations. For example; jazz, rock, R & B, news, country, talk, and the like.
A typical commercial AM or FM radio broadcast signal has an effective coverage radius of from about 30 to 60 miles. Most persons routinely travel distances that exceed the range of any one broadcast station; for example, when commuting, traveling on vacation, or as part of their jobs. Thus, as persons move from one broadcast area (market) to another, they must search manually for a station that is in range and has their preferred program style. When on vacation or taking other long excursions, persons usually have no knowledge of the broadcast programming available along a given route, and, thus, cannot readily find a station suited to their needs.
A Radio Data System (RDS) service was adopted in the United States in 1993. RDS applies only to VHF-FM broadcast stations, however. The service allows an FM station to encode a signal corresponding to a program type (PTY code) on a sub-carrier of the station's broadcast signal. Specially equipped FM-RDS receivers can operate to respond only to stations transmitting a desired program type code in response to button entries by a listener. Relatively few FM-RDS receivers have been put to use since adoption of the service in the United States. As a result, FM broadcast stations that encode RDS data on their signals also remain few in number.
Software known as "ID Logic" has been offered for use with broadcast receivers. As advertised, ID Logic equipped receivers use an "in-receiver database" of over 40,000 broadcast stations, with various different program types and other information stored for the stations.